Method for adjusting a valve

ABSTRACT

A method for the adjustment of the dynamic medium flow quantity of an electromagnetically actuated injection valve by an axial relative movement between the body of the valve and at least one guide element which at least partially circumferentially surrounds the valve&#39;s magnet coil on the circumference of the valve body. The ratio of magnetic useful flux to magnetic leakage flux, and thus the magnetic force, are varied so that the medium flow quantity can be influenced and adjusted. The final fixation of the at least one guide element takes place, for instance, by means of cementing, welding, clamping elements or resilient additional parts.

FIELD OF THE INVENTION

The present invention relates to a method for adjusting a valve and moreparticularly to a method for adjusting the dynamic medium flow quantityof an electromagnetically actuatable valve.

BACKGROUND INFORMATION

In known valves, the dynamic medium flow quantity given off during theopening and closing operation is set by the value of the elastic forceof a return spring acting on the valve closure member. The valve knownfrom German Unexamined Patent Application No. 37 27 342 has anadjustment bolt which is displaceably arranged in a longitudinal bore ofthe internal pole and against one end of which one end of the returnspring rests. The depth of insertion of the adjustment bolt into thelongitudinal bore of the internal pole determines the value of theelastic force of the return spring. From German Unexamined PatentApplication No. 29 42 853 there is known a valve in which the elasticforce of the return spring is adjusted by the screwed-in depth of anadjustment screw which can be screwed into the longitudinal bore of theinternal pole and against the one end of which one end of the returnspring rests.

The adjusting of the dynamic medium flow quantity by the adjustment ofthe elastic force of the return spring which acts on the valve closuremember has, however, the disadvantage that on the completely assembledvalve there must be provided a possibility to access the return springin the form of an easily accessible adjustment element on which anadditional seal must be provided.

From European Patent No. 0 301 381 there is already known a method foradjusting the injected quantity of fuel of a fuel injection valvewherein an adjustment tube is introduced up to a predetermined lengthinto a longitudinal bore of a tubular connection piece, the adjustmenttube is temporarily fixed in position within the connection piece bypress fitting or caulking, the adjustment tube being finally adjustedduring verification of the actual quantity of fuel injected and fixed inposition in the longitudinal bore of the connection piece by caulking anexternal circumferential section of the connection piece. This knownadjustment method has the disadvantage that, after the final adjustingof the adjustment tube, there is still required as additional operationthe fixing in position of the adjustment tube by caulking the externalcircumferential section of the connection piece and thus deforming theinjection valve. Due to the caulking there is the danger that theposition of the adjustment tube and thus the quantity of fuel set arechanged.

In order to avoid this danger, it has already been proposed in GermanPatent Application No. P 42 11 723.3 to employ a slit adjustment sleevewhich is under an initial tension acting in radial direction whereby thecaulking of an external circumferential section of the connection piecefor the final fixing in position of said adjustment sleeve in theconnection piece is no longer required. The adjustment sleeve thereforeassumes its defined position without any deformation of the valve andthe medium flow quantity adjusted in final manner is not subject tosubsequent changes.

All injection valves which are already known have in common thatmanipulations with adjustment tools inside the injection valve arerequired due to the adjusting of differently developed adjustmentelements such as adjustment bolts, adjustment screws, adjustment tubesor adjustment sleeves. This results, in each case, in high demands onthe quality of the adjustment elements and on a defined manipulation ofthe adjustment tools so as to avoid deformations within the injectionvalve. Furthermore, upon the insertion of an adjustment tool into theinjection valve, there is always a danger of dirtying. In addition,there is also the danger of the formation of chips upon the movement ofthe adjustment element inside the injection valve which may have aparticularly detrimental effect upon the operation of the injectionvalve.

SUMMARY OF THE INVENTION

The method, in accordance with the present invention, for adjusting thedynamic medium flow quantity given off by an electromagneticallyactuated injection valve, has the advantage that the dynamic medium flowquantity can be adjusted in a simple manner outside the medium flow pathand no adjustment element is required inside the injection valve andtherefore no adjustment tools are inserted into the injection valve.Thus, a cumbersome adjustment inside the injection valve is avoided andany danger of deformations by caulking or some other fixing in positionof an adjustment element inside the injection valve is eliminated, andthe risk of dirtying is greatly reduced.

In accordance with the present invention, the adjustment of the dynamicmedium flow quantity takes place instead on the circumference of theinjection valve by axial displacement of at least one guide elementwhich is developed, for instance, as a yoke and serves as aferromagnetic element. The at least one guide element surrounds a magnetcoil in circumferential direction, at least in Dart, and contacts a corewhich serves as a fuel inlet connection piece and with which the atleast one guide element is firmly connected in a final manner. The axialdisplacement of the at least one guide element along a valve body, whichis held fast in its position, has the result that the ratio of magneticuseful flux to magnetic leakage flux changes over the core and the atleast one guide element, entailing a change in the magnetic force sothat the dynamic medium flow quantity given off can be influenced andadjusted. Another possibility of adjusting the dynamic medium flowquantity consists in holding the at least one guide element fast bymeans of a holding tool and moving the valve body axially. The decisivefactor for the change of the ratio of magnetic useful flux to magneticleakage flux is a relative movement of the mounted valve body withrespect to the at least one guide element.

BRIEF DESCRIPTION OF THE DRAWING

The FIGURE shows an adjustable electromagnetically actuated injectionvalve in accordance with the present invention.

DETAILED DESCRIPTION

The electromagnetically actuatable valve shown by way of example in thedrawing in the form of an injection valve for fuel injection systems ofmixture-compressing internal combustion engines with externally suppliedignition has a tubular core 2 which is surrounded by a magnetic coil 1and serves as a fuel inlet connection piece. A coil form 3 stepped inthe radial direction receives a winding of the magnet coil 1 and,together with the core 2 of constant outside diameter, makes aparticularly compact and short structure of the injection valve possiblein the region of the magnet coil 1.

A tubular and thin-walled sleeve 12 which serves as a connecting part isconnected in a sealed manner to a lower end 9 of the core 2 and isconcentric to a longitudinal axis 10 of the valve. The sleeve 12 isconnected to the core 2 for instance by welding by means of a first weldseam 13, with said sleeve in part axially surrounding the core end 9 byan upper sleeve section 14. The stepped coil form 3 extends partiallyover the core 2 and, by a step 15 of larger diameter, over the sleevesection 14 of the sleeve 12 at least partially in the axial direction.The tubular sleeve 12 consisting, for instance, of non-magnetic steelextends downstream over a central sleeve section 17 and a lower sleevesection 18 directly up to a downstream termination 20 of the entireinjection valve. The sleeve 12 forms in this connection over its entireaxial length a passage opening 21 of constant diameter which extendsconcentric to the longitudinal axis 10 of the valve. With its centralsection 17 the sleeve 12 circumferentially surrounds an armature 24,while the sleeve 12 circumferentially surrounds with its lower section18 a valve seat member 25 and a spray orifice disk 26.

In the passage opening 21 there is arranged a very short valve needle 28which is developed, for instance, as a tube which is integral with thearmature 24 and which extends downstream out of the armature 24. Thevalve needle 28 is connected, for instance by welding, at its downstreamend 29 facing the spray orifice disk 26 to a, for instance, sphericalvalve closure member 30 on the circumference of which there are, forinstance, provided five flattenings 31.

The actuation of the injection valve takes place electromagnetically ina known manner. The electromagnetic circuit with magnet coil 1, core 2and armature 24 serves for the axial movement of the valve needle 28 andthus for the opening against the elastic force of a return spring 33 orfor the closing of the injection valve. A guide opening 34 of the valveseat member 25 serves for guiding the valve closure member 30 during theaxial movement of the valve needle 28 and the armature 24 along thelongitudinal axis 10 of the valve. The spherical valve closure member 30cooperates with a valve seat surface 35 of the valve seat member 25,which surface 35 tapers in the direction of flow in the manner of atruncated cone and is developed in the axial direction between the guideopening 34 and a lower end 36 of the valve seat member 25. Thecircumference of the valve seat member 25 has a slightly smallerdiameter than the passage opening 21 of the sleeve 12. At its end 36facing away from the valve closure member 30, the valve seat member 25is connected concentrically and firmly, for instance by acircumferential hermetic second weld seam 37, to the, for instance,cup-shaped spray orifice disk 26.

In addition to a bottom part 38 to which the valve seat member 25 isattached and in which at least one, for instance four, spray orifices 39formed by erosion or punching extend, the cup-shaped spray orifice disk26 has a circumferential holding edge 40 which extends in the downstreamdirection. The holding edge is bent downstream conically outward so thatit rests with radial pressure against the inner wall of the sleeve 12defined by the passage opening 21. At its downstream end, the holdingedge 40 of the spray orifice disk 26 is connected to the wall of thesleeve 12, for instance by a circumferential and hermetic third weldseam 42 produced, for instance, by means of a laser. A direct flowing ofthe fuel into an intake line of the internal combustion engine outsidethe spray orifices 39 is avoided by the weld seams 37 and 42. Due to thetwo weld seams 13 and 42, there are thus present two points ofattachment of the sleeve 12.

Contrary to the injection valves already known, no adjustment element,such as an adjustment tube or adjustment sleeve, is fitted into astepped flow bore 43 of the core 2 which extends concentric to thelongitudinal axis 10 of the valve and serves for feeding the fuel in thedirection of the valve seat surface 35. Therefore, the quality of theinternal wall of the flow bore 43 in the core 2 is not subject toparticularly high requirements. In the region of the end 9 of the corethe flow bore 43 is developed in such a manner that the return spring 33presses against an upper contact surface 44 which is created by a stepin the flow bore 43. Immediately upstream of the contact surface 44, theflow bore 43 has a clearly smaller diameter than in an opening 45 intowhich the return spring 33 extends and the upstream limitation of whichis formed by the contact surface 44. The return spring 33 thereforerests with its upper end against the contact surface 44 in the core 2while the lower end of the return spring 33 rests against a shoulder 46in the armature 24 at which the transition to the tubular valve needle28 takes place. The return spring 33 extends in the axial directionpartially within the flow bore 43 of the core 2 and also up to theshoulder 46 within a concentric stepped armature opening 47 in thearmature 24.

The depth of insertion of the valve seat member 25 having the cup-shapedspray orifice disk 26 is decisive for the stroke of the valve needle 28.In this connection, the one end position of the valve needle 28, whenthe magnet coil 1 is not excited, is determined by application of thevalve closure member 30 against the valve seat surface 35 of the valveseat member 25 while the other end position of the valve needle 28results, when the magnet coil 1 is excited, from the application of thearmature 24 with its upper end 49 against a lower end 50 of the core end9.

A fuel filter 52 is arranged in the stepped flow bore 43 of the core 2upstream of the return spring 33. The magnet coil 1 is surrounded by atleast one guide element 53 which is developed, for instance, as a yoke,serves as a ferromagnetic element and which at least partially surroundsthe magnet coil 1 in the circumferential direction. The at least oneguide element 53 rests with its one end against the core 2 and with itsother end against the central sleeve section 17 of the sleeve 12 and canbe connected to the latter, for instance by welding 73, soldering 74, orcementing 75.

The completely adjusted injection valve is substantially surrounded by aplastic injection molding 55 which, proceeding from the core 2, extendsin the axial direction via. the magnet coil 1 and the at least one guideelement 53 down to the downstream termination 20 of the injection valve,the injection molding 55 including an electrical cable connector 56 alsoinjection-molded thereon.

By means of the tubular sleeve 12 the injection valve can be builtparticularly short and compact as well as in a cost-favorable manner. Byusing the relatively inexpensive sleeve 12, it becomes possible todispense with the rotating parts customary in injection valves such asvalve seat carriers or nozzle holders which are more voluminous due totheir larger outside diameter and more expensive in their manufacturethan the sleeve 12.

In order to simplify the installation of the sleeve 12, the sleeve 12has, at its two axial ends, for instance, slightly radially outward bentcircumferential edges 58 and 59. The upstream circumferential edge 58 isreceived in an intermediate space 60 which is formed between the step 15of the coil form 3 and the core end 9 of the core 2 and into which theupper sleeve section 14 of the sleeve 12 partially extends. Thedownstream circumferential edge 59 is located in the region of the thirdweld seam 42 which hermetically connects the sleeve 12 and the sprayorifice disk 26, it being possible in this connection for the downstreamend of the sleeve 12 and thus also of the downstream circumferentialedge 59 to lie at the same axial height as the termination 20 of theinjection valve and therefore slightly outside the weld seam 42.

Due to the firm and hermetic connections of the sleeve 12 to the core 2and the spray orifice disk 26 and thus also the valve seat member 25 bythe weld seams 13 and 42, only the armature 24 with the valve needle 28arid the valve closure member 30 welded thereon, as well as the returnspring 33 can move within the sleeve 12. Since the armature 24 has onlya slightly smaller outside diameter than the inner wall of the sleeve12, the armature 24 is guided in the sleeve 12, namely in the centralsleeve section 17. In the armature 24 and downstream of the armatureopening 47, there is developed at least one fuel duct 62 which isconnected to said armature opening 47 and which extends in the axialdirection through the armature 24, thus assuring that the fuel passesinto the valve seat member 25.

In addition to the reduction in the outside diameter of the injectionvalve by employing the sleeve 12, the axial length is also clearlyreduced as compared with similar injection valves. The armature 24 andthe valve needle 28 namely have a substantially smaller axial lengththan known injection valves. The at least one guide element 53 which isdeveloped in the form of a yoke contacts the sleeve 12 at its centralsleeve section 17 and therefore precisely in the region where thearmature 24 is located within the sleeve 12. The magnetic flux is thusconducted from the at least one guide element 53 directly via thenon-magnetic sleeve 12 to the armature 24.

The methods of the invention for adjusting the dynamic medium flowquantity given off during the opening and closing operation of the valveshown by way of example in the drawing are characterized by a relativemovement of the installed valve body, consisting at least of magnet coil1, core 2, coil form 3, sleeve 12, armature 24, valve seat member 25,spray orifice disk 26, valve closure member 30 and return spring 33,with respect to the at least one guide element 53. The arrows designatedA and B indicate the axial movements, with arrow A indicating that thevalve body is held fast during the adjusting operation and that the atleast one guide element 53 is moved, while arrow B indicates that the atleast one guide element 53 is held fast by a holding device 70 while atthe same time an axial displacement of the valve body takes place.

In a first method according to the present invention for the adjustmentof the dynamic medium flow quantity given off, the installation of thesubassemblies in the valve takes place in a known manner. The actualadjustment of the medium flow quantity given off commences only once thefirm connections of the sleeve 12 to the core 2 by the first weld seam13 and of the sleeve 12 to the spray orifice disk 26 and thus the valveseat member 25 by the third weld seam 42 have been created and thereforeonly once the valve seat member 25, the armature 24 with the valveneedle 28 and the return spring 33 have been installed. The stroke ofthe valve needle 28 results from the depth of insertion of the valveseat member 25, said stroke being thus definitively set. Before thevalve body which has been installed in this manner is provided with theplastic injection molding 55, the adjustment of the dynamic medium flowquantity takes place. For this purpose, the at least one guide element53 is applied against the core 2 and the sleeve 12 in theabove-described regions and is temporarily held fast by a holding device70. The clamping and pressing of the at least one guide element 53against the core 2 and the sleeve 12 is effected, for instance, by theresilient holding device 70 with only small elastic forces so as toavoid deformations on the guide element 53 or on the valve body as wellas changes in the adjustment of the stroke set for the valve needle 28.

The injection valve is thereupon contacted hydraulically and connectedto an electronic control device 71. Current pulses having correspondingcontrol frequencies are then applied to the magnet coil 1. In theelectromagnetic circuit a magnetic field is formed around the magnetcoil 1 so that a magnetic flux occurs via the core 2, the armature 24and the at least one guide element 53. The electromagnetic circuitserves for the axial movement of the valve needle 28 and thus for theopening against the elastic force of the return spring 33 or for theclosing of the injection valve respectively. The magnetic flux can bedivided into two components, namely into a magnetic useful flux 64 whichis indicated by a dashed line and a magnetic leakage flux 65 indicatedby a dotted line. By the axial displacement of one or two guide,elements 53 (arrow A) with respect to the valve body which is held fastin its position, the ratio of magnetic useful flux 64 to magneticleakage flux 65 can now be influenced. An axial displacement of the atleast one guide element 53, for instance in the upward direction andtherefore away from the armature 24, has the result that the ratio ofmagnetic useful flux 64 to magnetic leakage flux 65 is changed to thedetriment of the magnetic useful flux 64. For this reason, the magneticforce decreases and the dynamic medium flow quantity given off isreduced.

This adjustment operation therefore takes place with a medium flowingthrough the injection valve. By means, for instance, of a measuringvessel 72, the dynamic actual medium quantity given off during theopening and closing operation is measured and compared with a desiredmedium quantity. If the actual medium quantity measured and thepredetermined desired medium quantity do not agree, then the at leastone guide element 53 is displaced in the axial direction by means of atool 80 along the valve body which is held fast in its position untilthe ratio of magnetic useful flux 64 to magnetic leakage flux 65 reachessuch a value that the actual medium quantity measured is in agreementwith the predetermined desired medium quantity.

Only then is the final fixing in position of the at least one guideelement 53 on the valve body effected. Various connection techniques canbe used for this, on the one hand for instance firm connections bywelding 73, soldering 74 or cementing 75 of the at least one guideelement 53 on the core 2 and on the sleeve 12. It is furthermorepossible to provide prior to the coating of the injection valve byinjection molding by means of a valve injection molding die at least oneresilient additional part 76, for instance an annular spring,circumferential over the at least one guide element 53. The plasticinjection molding 55 then ultimately completely covers the at least oneguide element 53 with the resilient additional part 76. Anotherattachment variant for the guide element 53 consists in providing aclamping device ill the valve injection molding die so that the at leastone guide element 53 is held fast directly by said valve injectionmolding die. Upon the injection molding, the clamping elements providedin the die are removed in accordance with a predetermined sequence.

A second method according to the present invention for the adjustment ofthe dynamic medium flow quantity given off differs from the first methodaccording to the invention only by the fact that, in this case, the atleast one guide element 53 is held in its position, for instance in aresilient holding device 70, and the valve body is moved axially alongthe at least one guide element 53, as shown diagrammatically by thearrow B. The adjustment operation then takes place analogously to thefirst method according to the present invention until the actual mediumquantity measured agrees with the predetermined desired medium quantity.The final fixing in position of the at least one guide element 53 isalso effected by one of the variants described with respect to the firstmethod according to the present invention.

In a third method according to the present invention for the adjustmentof the dynamic medium flow quantity given off, the installation of thesubassemblies in the valve also takes place in a known manner. Theactual adjustment of the medium flow quantity given off commences onlyonce the firm connections of the sleeve 12 to the core 2 by the firstweld seam 13 and of the sleeve 12 to the spray orifice disk 26 and thusof the valve seat member 25 by the third weld seam 42 have been createdand therefore only once the valve seat member 25, the armature 24 withthe valve needle 28 and the return spring 33 have been installed.

The stroke of the valve needle 28 results from the depth of insertion ofthe valve seat member 25, the stroke being thus definitively adjusted.Before the valve body which has been installed in this manner isprovided with the plastic injection molding 55, the dynamic medium flowquantity is adjusted. For this purpose, the at least one guide element53, is applied in the above-described regions against the core 2 and thesleeve 12 and temporarily held fast by a holding device 70. The clampingand pressing of the at least one guide element 53 against the core 2 andthe sleeve 12 is effected, for instance, by a resilient holding device70 with only small elastic forces so as to avoid deformations on theguide element 53 or the valve body and changes in the adjustment of thestroke set for the valve needle 28.

The injection valve is thereupon contacted and connected to anelectronic control device 71. Current pulses having correspondingcontrol frequencies are then applied to the magnet coil 1. In theelectromagnetic circuit a magnet field is formed around the magnet coil1 so that a magnetic flux occurs via the core 2, the armature 24 and theat least one guide element 53. The electromagnetic circuit serves forthe axial movement of the valve needle 28 and thus for the openingagainst the elastic force of the return spring 33, or for the closing ofthe injection valve, respectively. The magnetic flux can be divided intotwo components, namely a magnetic useful flux 64 which is indicated by adashed line and a magnetic leakage flux 65 indicated by a dotted line.By the axial displacement of one or two guide elements 53 (arrow A) withrespect to the valve body which is held fast in its position, the ratioof magnetic useful flux 64 to magnetic leakage flux 65 can now beinfluenced. An axial displacement of the at least one guide element 53has the result that the ratio of magnetic useful flux 64 to magneticleakage flux 65 changes. As a result thereof, the magnetic force assumesdifferent values and the operating time and release time of the armature24 change so that the opening and closing duration of the valve closuremember 30 on the valve seat surface 35 is influenced.

This adjustment operation takes place dry, i.e. no medium flows throughthe injection valve. The operating and release times of the armature 24are the decisive parameters for adjusting the dynamic medium flowquantity. Before any exact adjustment can take place, a correlationbetween operating and release times and the medium flow quantities mustbe established. Only in this way can the operating and release timesmeasured upon the adjustment operation be converted into comparablevalues for the medium flow quantities. The at least one guide element 53is displaced in the axial direction by means of a tool 80 along thevalve body held fast in its position until the ratio of magnetic usefulflux 64 to magnetic leakage flux 65 reaches such a value that themeasured operating and release times of the armature 24 assume thepredetermined values which are related to the medium flow quantities tobe given off.

Only then is the final fixing in position of the at least one guideelement 53 effected. For this purpose, various connection techniques canbe employed, for instance, firm connections by welding 73, soldering 74,or cementing 75 of the at least one guide element 53 to the core 2 andthe sleeve 12. It is, furthermore, possible to apply, prior to thecoating of the injection valve by injection molding by means of a valveinjection molding die, at least one resilient additional part 76, forinstance an annular spring, circumferentially over the at least oneguide element 53. The plastic injection molding 55 then ultimatelycompletely covers the at least one guide element 53 with the resilientadditional part 76. Another attachment variant for the guide element 53consists in providing a clamping device in the valve injection moldingdie so that a holding fast of the at least one guide element 53 takesplace directly by said valve injection molding die. Upon the injectionmolding, the clamping elements provided in the die are removedaccordance with a predetermined sequence.

The principle of the dry adjustment of the third method according to thepresent invention can also be used in a fourth method according to thepresent invention in which the principle of the valve body displacementdescribed in the second method of the invention is employed. In thiscase, therefore, the relative movement between the at least one guideelement 53 and the valve body is again achieved in the manner that theat least one guide element 53 is held fast in its position, for instancea resilient holding device 70, and the valve body is moved axially(arrow B) along the at least one guide element 53. In other respects,the adjustment operation takes place in an analogous manner, and allvariants already mentioned above of the attachment of the at least oneguide element 53 on the core 2 and on the sleeve 12 are possible.

What is claimed is:
 1. A method for adjusting a dynamic medium flowquantity given off by an electromagnetically actuatable valve having avalve body which includes a core surrounded by a magnet coil, aconnection part extending along a longitudinal axis of the valve, avalve seat member which is connected to the connection part and has afixed valve seat surface, an armature which can be displaced within theconnection part, and a valve closure member which can be actuated by thearmature against a force of a return spring and which cooperates withthe fixed valve seat surface, comprising the steps of:applying andtemporarily holding against the valve body at least one guide elementwhich is developed as a yoke, serves as a ferromagnetic element, extendsin an axial direction from the core to the connection part over themagnet coil, and at least partially surrounds the magnet coilcircumferentially; connecting the valve to a medium supply; applyingcurrent pulses from a control device to the magnet coil, whereby amagnetic field is formed; measuring an actual dynamic medium quantitygiven off during opening and closing of the valve; comparing the actualdynamic medium quantity measured with a predetermined desired mediumquantity; holding the valve body in a fixed position; displacing the atleast one guide element in the axial direction along the valve bodyuntil the actual dynamic medium quantity measured substantially equalsthe predetermined desired medium quantity; fixing in position the atleast one guide element on the valve body; and covering the valve bodyand the at least one guide element, at least in part, with a plasticinjection molding.
 2. The method according to claim 1, wherein the atleast one guide element is temporarily held against the valve body by aresilient holding device.
 3. The method according to claim 1, whereinthe step of fixing the at least one guide element on the valve bodyincludes cementing.
 4. The method according to claim 1, wherein the stepof fixing the at least one guide element on the valve body includeswelding.
 5. The method according to claim 1, wherein the step of fixingthe at least one guide element on the valve body includes soldering. 6.The method according to claim 1, wherein the step of fixing the at leastone guide element on the valve body is preceded by surrounding the atleast one guide element by a resilient additional part which presses theat least one guide element against the valve body.
 7. The methodaccording to claim 1, wherein the step of fixing the at least one guideelement on the valve body includes holding the at least one guideelement by clamping elements arranged in a valve injection molding die.8. A method for adjusting a dynamic medium flow quantity given off by anelectromagnetically actuatable valve having a valve body which includesa core surrounded by a magnet coil, a connection part extending along alongitudinal axis of the valve, a valve seat member which is connectedto the connection part and has a fixed valve seat surface, an armaturewhich can be displaced within the connection part, and a valve closuremember which can be actuated by the armature against a force of a returnspring and which cooperates with the fixed valve seat surface,comprising the steps of:applying and temporarily holding against thevalve body at least one guide element which is developed as a yoke,serves as a ferromagnetic element, extends in an axial direction fromthe core to the connection part over the magnet coil, and at leastpartially surrounds the magnet coil circumferentially; connecting thevalve to a medium supply; applying current pulses from a control deviceto the magnet coil, whereby a magnetic field is formed; measuring anactual dynamic medium quantity given off during opening and closing ofthe valve; comparing the actual dynamic medium quantity measured with apredetermined desired medium quantity; holding the at least one guideelement in a fixed position; displacing the valve body in the axialdirection witch respect to the at least one guide element until theactual medium quantity measured substantially equals the predetermineddesired medium quantity; fixing in position the at least one guideelement on the valve body; and covering the valve body and the at leastone guide element, at least in part, with a plastic injection molding.9. The method according to claim 8, wherein the at least one guideelement is temporarily held against the valve body by a resilientholding device.
 10. The method according to claim 8, wherein the step offixing the at least one guide element on the valve body includescementing.
 11. The method according to claim 8, wherein the step offixing the at least one guide element on the valve body includeswelding.
 12. The method according to claim 8, wherein the step of fixingthe at least one guide element on the valve body includes soldering. 13.The method according to claim 8, wherein the step of fixing the at leastone guide element on the valve body is preceded by surrounding the atleast one guide element by a resilient additional part which presses theat least one guide element against the valve body.
 14. The methodaccording to claim 8, wherein the step of fixing the at least one guideelement on the valve body includes holding the at least one guideelement by clamping elements arranged in a valve injection molding die.15. A method for adjusting a dynamic medium flow quantity given off byan electromagnetically actuatable valve having a valve body whichincludes a core surrounded by a magnet coil, a connection part extendingalong a longitudinal axis of the valve, a valve seat member which isconnected to the connection part and has a fixed valve seat surface, anarmature which can be displaced within the connection part, and a valveclosure member which can be actuated by the armature against a force ofa return spring and which cooperates with the fixed valve seat surface,comprising the steps of:applying and temporarily holding against thevalve body at least one guide element which is developed as a yoke,serves as a ferromagnetic element, extends in an axial direction fromthe core to the connection part over the magnet coil, and at leastpartially surrounds the magnet coil circumferentially; applying currentpulses from a control device to the magnet coil, ,whereby a magneticfield is formed and the armature is displaced; measuring ,operating andreleasing times of the armature; comparing the measured operating andreleasing times of the armature with predetermined operating andreleasing times; holding the valve body in a fixed position; displacingthe at least one guide element in the axial direction along the valvebody until the measured operating and releasing times of the armaturesubstantially equal the predetermined values; fixing in position the atleast one guide element on the valve body; and covering the valve bodyand the at least one guide element, at least in part, with a plasticinjection molding.
 16. The method according to claim 15, wherein the atleast one guide element is temporarily held against the valve body by aresilient holding device.
 17. The method according to claim 15, whereinthe step of fixing the at least one guide element on the valve bodyincludes cementing.
 18. The method according to claim 15, wherein thestep of fixing the at least one guide element on the valve body includeswelding.
 19. The method according to claim 15, wherein the step offixing the at least one guide element on the valve body includessoldering.
 20. The method according to claim 15, wherein the step offixing the at least one guide element on the valve body is preceded bysurrounding the at least one guide element by a resilient additionalpart which presses the at least one guide element against the valvebody.
 21. The method according to claim 15, wherein the step of fixingthe at least one guide element on the valve body includes holding the atleast one guide element by clamping elements arranged in a valveinjection molding die.
 22. A method for adjusting a dynamic medium flowquantity given off by an electromagnetically actuatable valve having avalve body which includes a core surrounded by a magnet coil, aconnection part extending along a longitudinal axis of the valve, avalve seat member which is connected to the connection part and has afixed valve seat surface, an armature which can be displaced within theconnection part, and a valve closure member which can be actuated by thearmature against a force of a return spring and which cooperates withthe fixed valve seat surface, comprising the steps of:applying andtemporarily holding against the valve body at least one guide elementwhich is developed as a yoke, serves as a ferromagnetic element, extendsin an axial direction from the core to the connection part over themagnet coil, and at least partially surrounds the magnet coilcircumferentially; applying current pulses from a control device to themagnet coil, whereby a magnetic field is formed and the armature isdisplaced; measuring operating and releasing times of the armature;comparing the measured operating and releasing times of the armaturewith predetermined operating and releasing times; holding the at leastone guide element in a fixed position; displacing the valve body in theaxial direction with respect to the at least one guide element until themeasured operating and releasing times of the armature substantiallyequal the predetermined values; fixing in position the at least oneguide element on the valve body; and covering the valve body and the atleast one guide element, at least in part, with a plastic injectionmolding.
 23. The method according to claim 22, wherein the at least oneguide element is temporarily held against the valve body by a resilientholding device.
 24. The method according to claim 22, wherein the stepof fixing the at least one guide element on the valve body includescementing.
 25. The method according to claim 22, wherein the step offixing the at least one guide element on the valve body includeswelding.
 26. The method according to claim 22, wherein the step offixing the at least one guide element on the valve body includessoldering.
 27. The method according to claim 22, wherein the step offixing the at least one guide element on the valve body is preceded bysurrounding the at least one guide element by a resilient additionalpart which presses the at least one guide element against the valvebody.
 28. The method according to claim 22, wherein the step of fixingthe at least one guide element on the valve body includes holding the atleast one guide element by clamping elements arranged in a valveinjection molding die.